The abundance of non-starch polysaccharides (NSPs) in the diets of monogastric and ruminant animals can adversely affect the nutritional value of feed, and also present an opportunity to improve nutritional content if they can be degraded in the diet or converted into beneficial nutritional components. NSPs are among the primary structural components of plant cell wall (cellulose, hemicellulose, xyloglucans, arabionxylans, galactans, arabinogalactans, etc.) and can also serve as carbohydrate storage reserves in some plants. Additionally, pectins and gums are considered non-cell wall NSP. Because of their various structural and biological roles, NSPs often bind or encase the starch, proteins, fats and other nutrients that are present in plant-based feed ingredients (such as cereals, legumes, silage etc.) and other ingredients, inhibiting the animal's ability to digest nutrients efficiently. Increased levels of NSPs in the diet may increase viscosity of intestinal contents, which can interfere with digestive enzymes and reduce the digestibility of nutrients, thereby increasing feed conversion (mass of feed divided by the mass of meat produced) and reducing body weight gain (Iji, P. A. 1999. The impacts of cereal non-starch polysaccharides on intestinal development and function in the broiler chickens. Worlds Poult. Sci. J. 55:375-387, which is incorporated herein by reference as if fully set forth). For example, feeding increasing levels of guar meal germ (0, 5, or 7.5%) or guar meal hulls (0, 2.5, or 5%) to broilers resulted in increasing digesta viscosity (Lee, J. T., C. A. Bailey, and A. L. Cartwright. 2003. β-Mannanase ameliorates viscosity-associated depression of growth in broiler chickens fed guar germ and hull fractions. Poult. Sci. 82:1925-1931, which is incorporated herein by reference as if fully set forth). In addition to increasing the viscosity, body weight gain and feed conversion was also worse with increasing guar meal hull, demonstrating the negative effects of high viscosity on animal performance.
NSPs have also been known to inadvertently trigger immune responses in the gut, which may further detract from efficiency of feed utilization and have implications for animal health.
In addition to the cereal components, diets now also routinely contain DDGS (dried distillers grains and solubles) that is also not easily digested. Multiple studies have shown that enzyme supplementation can increase diet metabolizable energy (ME), and, or, decrease the viscosity of diets containing high levels of wheat, barley, DDGSs, or other fibrous components. The addition of carbohydrases to corn-soybean meal-based broiler diets, when formulated to have a 3% reduction in dietary ME, has been accomplished without compromising the feed conversions of broilers reared under either hot or cool seasons. It has been determined that the hydrolyzed β-d-glucan is responsible for improved growth.